Various electronic devices are mounted on a vehicle. For distributing the electric power to the various electronic devices, an electrical junction box is arranged at a proper position in the vehicle. Depending on a car type, electrical junction boxes having various structures are used. For example, like an electrical junction box disclosed in Patent Document 1, there is an electrical junction box for distributing electric power using a metal core substrate.
Further, as shown in FIG. 7, an electrical junction box 510 using a core metal plate 502 of a metal core substrate 501 for not only radiation but also a part of an electric power distributing circuit is known. This electrical junction box 510 distributes electric power from a battery and an alternator to a plurality of electronic devices, and includes: one metal core substrate 501; a plurality of electronic components mounted on a surface of the metal core substrate 501; a connector 507a connected to the battery; a connector 507b connected to the alternator; and a not-shown case receiving them.
The metal core substrate 501 is provided with one core metal plate 502; insulating layers 504a, 504b covering a surface of the core metal plate 502; and conductor patterns 505 formed on the insulating layers 504a, 504b. Further, the conductor patterns 505 are made of copper foil.
The connector 507a is composed of an L-shaped terminal 571a and a connector housing 570a. The terminal 571a is provided with a first connecting portion 572a connected to a connector of a wiring harness connected to the battery, and a second connecting portion 573a attached to the metal core substrate 501. The first connecting portion 572a is disposed on an inside of the connector housing 570a. The second connecting portion 573a is attached to the metal core substrate 501 in a manner penetrating the metal core substrate 501, electrically connected to the conductor patterns 505, and isolated from the core metal plate 502.
The connector 507b is composed of an L-shaped terminal 571b and a connector housing 570b. The terminal 571b is provided with a first connecting portion 572b connected to a connector of a wiring harness connected to the alternator, and a second connecting portion 573b attached to the metal core substrate 501. The first connecting portion 572b is disposed on an inside of the connector housing 570b. The second connecting portion 573b is attached to the metal core substrate 501 in a manner penetrating the metal core substrate 501, and electrically connected to the conductor patterns 505 and the core metal plate 502.
In this way, in the electrical junction box 510, an electric power distribution circuit from the battery is only composed of the conductor patterns 505 formed on surfaces of the insulating layers 504a, 504b, and an electric power distribution circuit from the alternator is composed of the conductor patterns 505 and the core metal plate 502. However, in the electric power distribution circuit from the battery, because a thickness of the conductor patterns 505 is thinner than that of the core metal plate 502, the conductor patterns 505 need a large surface area, thereby there is a problem that the metal core substrate 501 becomes upsized.
In view of this problem, as an electrical junction box 610 shown in FIG. 8, a straight slit is formed on a core metal plate 602 to split the core metal plate 602, and one split portion 602a is used as the electric power distribution circuit from the battery, and the other split portion 602b is used as the electric power distribution circuit from the alternator. Thereby, the metal core substrate 601 is prevented from being upsized.
Further, reference signs 604a, 604b in FIG. 8 denote insulating layers for being embedded in the slit 603, and covering a surface of the core metal plate 602 to integrate the split core metal plate portions. Further, reference sign 605 in FIG. 8 denotes conductor patterns formed on the insulating layers 604a, 604b. Further, reference sign 570a in FIG. 8 denotes a connector connected to the battery similar to FIG. 7. Reference sign 570b denotes a connector connected to the alternator similar to FIG. 7.